With increasingly widespread use of electronic information networks, electronic publishing including electronic books is also used more widely. As an apparatus for electronic publishing and caused to display electronic data, a self-luminous or back-light display apparatus is used. However, when compared with printed paper as a medium, such a display apparatus is likely to cause fatigue when used for a long time for ergonomic reasons. In addition, power consumption thereof is heavy and when battery powered, the display time is limited. In contrast to such shortcomings, a reflection type display apparatus including electronic paper can reduce fatigue because characters can be read something like paper. In addition, display performance can be delivered outdoors in places where the sun or a light shines and so the reflection type display apparatus is also suitable for outdoor signboards. Moreover, the reflection type display apparatus can be powered for a long time because power consumption thereof is small. No power is consumed except when the screen is rewritten and therefore, electronic paper is also used for applications such as electronic signboards and electronic price tags and is actively developed.
The monochrome display is sufficient for only character information of an electronic book in electronic paper, but the colorized display is a technology necessary to display for illustrations of books, advertisements, signboards, the display to enhance the eye catch effect, images, catalogs and the like and needs thereof increase with the colorization of display content. Therefore, the following methods are proposed for color electronic paper.
For the colorization of electronic paper, a technique of using a plurality of microcapsules displaying R, G, and B in which electrophoretic particles are dispersed and sealed is proposed (Japanese Patent No. 4568429 and Japanese Patent No. 4207448).
For the colorization of electronic paper, a method of using a color filter is proposed. According to the method, the interval between pixels of the color filter is preferably 1 to 20 μm (Japanese Patent No. 4415525).
For the colorization of electronic paper, a method of inkjet-printing a colored region on various surfaces of an electro-optical display or corresponding surfaces of a front plane laminate, reverse front plane laminate, or double release film used to manufacture such a display is proposed (Jpn. PCT National Publication No. 2010-503895).
For the colorization of electronic paper, a method of producing a color filter layer by printing according to the inkjet method by fitting to a pattern displayed in a monochrome display is proposed.